Bit and bit clamp



Nov. 10, 1953 J. D. DANN BIT AND BIT CLAMP Filed Dec. 3, 1949 'lll INVENTOR. r/bmv D. Dam/v, fl/wM ATTORNEYS,

Patented Nov. 10, 1953 UNITED STATES PATENT our rice BITIAND BIT CLAMP John D; Dann; Cincinnati, Ohio, assignor to: 'llhei- Gincinnatt Mine Machinery Gincinnati, Ohio, at corporatiomof Ohio Application December 3, 1949, Serial? No. 130,887"

My invention relates to the improved holding of bits in mining machines utilizing an endless moving chain composed of a series of bit blocks linked together and similar to those well known in the art as exemplified by the bit block described in Patent No. 2,319,387 issued May 18, 1943 to Jol-m R. Ca-rtlidge and Armin- O; Bruestle.

In such a cutting chain; it is necessary that the cutting bits be rigidly held during the cutting operation, but which may be easily and quickly removed, reversed orchanged in the darkness" of a mineshaft; Itis also of primary importance that the cutting tip orsurfac'e of the bit may be adjustable in reference to its projection from the bit block, but which, after once adjusted, be maintained in its: adjusted position throughout the extremely-heavy wear and tear" oiithe' cutting. operation.

Recently, the use of tungsten carbide tipped bits have come into this held and since these bits: are. relatively expensive, the holding of the bit in the bit block to prevent or cut down loss of the": same; has: become:1 highly important.

It is anobject. of my invention to. provide a bit and bit clam for use in the well-known bit block of the type having a bit receiving aperture and bit retaining set" screw" holesoppositely dis posed fromtheaperture and in alignment with the direction of movement of the block.

The combination of bit and bit clamp may, of course, also be used on many of the existing types of cutting chains designed for use with the standard type bit, and it is not necessary to design a special chain in order to adapt it for use with this type of arrangement.

It is a further object of my invention to provide a bit and bit clamp for the above purpose which may be quickly and easily inserted in the aperture of the bit faced in either direction but which is retained in position against movement during the use of the chain in cutting coal or other material.

It is a further object of my invention to provide a bit and bit clamp which permits the easy adjustment of the projection of the cutting end of the bit from the bit block and wherein the clamping of the bit in place insures that the bit remain in its placed position at all times.

A further object of my invention is to provide a bit and bit clamp as described above which is relatively inexpensive to construct, but which is rugged in its action and which minimizes wear and tear on the bit block and the bit retaining set screw during operation.

These and other objects of my invention which will be set: forth hereinafter or beapparent to one skilled in the art upon. reading these specifications; F accomplish. by: that oer,- tainccnstruction and arrangement. oil parts; of:- which; I shall now describe an. exemplary em bod-i'mentz Reference is now made t'o the" drawings? which form a part thereof, and in whi'ch z Figure 1 is a front" elevation of a. bit block with my novel bit and bit clamp in placee Figure 2 is a; side elevation: of the bit block and bit shown in Figure" 1 with a. portion. 01'. the bit bl'ockin section.

Figure 3 is a perspective view: of my novel bit.

Figure 4 is a perspective viewoi' my: novel bit clamp adapted for use witlithe bi't' shown in Figure 3-.

Briefly, in the practice of my" invention, it provide a bit having a shank which is: adapted to be inserted and retained in the bit receiving aperture of the bit bl'ocki also provide abit clamp having a portion which bears against the leading edge of the bit shank and has a. lug adapted to be received in one of the bitre taining set screw holes disposed. from:- the bit receiving aperture. The portion of the clamp which bears: against the hit shank and the portion of the shank against which it bears have mating serrations which prevent the relative longitudinal movement of the clamp and the bit after the two are pressed together by a bit retaining set screw.

The bit and bit clamp may be easily reversed where necessary, since the lug on the clamp is adapted to be received and held by either set screw hole.

Referring to the drawings, the bit I has a shank portion 2 adapted to be received in the bit receiving aperture 3 of the bit block 4.

The bit shank 2 terminates into a cutting face 5 of a well-known type.

Bit blocks 4 of the type to which my invention relates have oppositely disposed and aligned bit retaining set screw holes 6. A set screw 1 is usually inserted in either one of the holes 6 depending upon the direction of movement of the block 4. In usual practice, the set screw 1 is positioned in the hole 6 which is leading in the movement of the block 4.

My novel bit clamp is shown in Figure 4 and consists of a fiat portion 8 having a rearwardly projecting lug 9. The surface of the portion 8 is serrated as at In and the rearward edge of the shank 2 carries mating serrations ll.

The bit I is inserted in the bit aperture 3 of the bit block 4, as shown in Figure 2 with the serrations II following the movement of the block 4. The clamp is positioned within the aperture 3 with the portion 8 within the aperture and the lug 9 snugly fitting in the set screw receiving hole 6. From this it is apparent that the serrations ID in the clamp mate with the serrations II in the shank 2 of the bit I. The set screw I is now inserted in the other set screw hole 6 A and taken up so that its end 'I' bears against the shank 2 of the bit I. This insures the close mating of the serrations I0 and II which prevents any longitudinal movement of the bit I. If it is desirable to merelyremove the bit and replace with a new bit or to adjust the projection of the bit I from the bit block i, it is only necessary to loosen the set screw i. This permits either removal of the bit I or an upward or downward movement of the same, registering different teeth in the serrations I0 and II. If it is desirable to reverse the bit I, the bit itself is removed as is the clamp portion. The set screw I is removed from its hole and inserted in the opposite hole; whereupon the clamp portion is again inserted in the aperture 3 with its lug 9 now projecting in the hole from which the set screw I was removed.

As is. apparent, the commercial construction of both the bit I and the clamp is relatively inexpensive. The serrations may be easily cut into the shank and clamped by either milling or an efiicient operating breaching operation will result in extreme accuracy and close fit. The set screw 1 preferably has a fiat point, thus eliminating the disadvantages of a cupped point.

, The bit is firmly held in the bit block and the thrust against the bit during operation is absorbed by the lug 53 which mates with the set screw hole in the block opposite the set screw hole carrying the set screw. Any outward force tending to loosen the bit is prevented by the mating serrations of the bit chain and clamp and is again borne by the lug 9 within the set screw hole 6.

As pointed out above, the bits in a machine of this ty e must resist very rough usage and I have provided a bit-and bit clamp which will 4 resist all normal strains without becoming injured or moving out of adjustment.

It is to be understood that modification may be made in my invention Without departing from the spirit thereof and I do not intend to limit myself otherwise than as pointed out in the claim which follows.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

In combination in a cutter chain, a bit block having a bit receiving aperture, an opposed pair of walls of which are vertically disposed and interrupted intermediate their upper and lower ends by opposed set screw holes extending outwardly through'the bit block, a bit clamp conlength, whereby to provide in said aperture an uninterrupted wall surface which is serrated throughout its length, a bit having a shank fitted in the aperture in said block between the said bit clamp and the opposite wall of the aperture, said shank having horizontally disposed serrations extending along the face thereof facing the body portion of said clamp, and a bit retaining set screw in the screw hole opposite said bit clamp, said set screw contacting the face of said bit opposite the face thereof containing said serrations, whereby to clamp the shank of said bit against the body portion of said clamp with the said serrations in mating engagement.

JOHN D. DANN.

References Cited in the file of this patent V UNITED STATES PATENTS Number Name Date 1,777,515 Cartlidge Oct. 7, 1930 2,394,813 Simmons Feb. 12, 1946 

